It is known that to wind a thread or wire, both if it is arriving from a source spool having a large diameter or if it arrives from a source such as an extruder, it is necessary to guide the thread in its winding movement. Normally, the thread is guided by means of a guiding pulley and the thread displaces itself laterally across the spool with respect to an origin, as a function of the thickness of the series of turns which are arranged beside one another. Alternatively, the thread is guided by a mechanical device. If, for whatever reason the thread is not suitably and carefully guided, a superposition of the turns takes place, such as in the case of guiding devices having a mechanical distributor, i.e. an irregular winding of the thread upon the spool takes place. This is particularly true in the case of spools of metal wire which are intended for particular uses in industry, such as spools of wire for welding, in welding machines of the continuous thread type.